Marine propeller



H. HAUSSMANN. MARINE PROPBLLBR.

No. 547,210. Y PAK Patented 001;. 1.1895.

Ntra raras rrrcn.

MARINE PROPELLER.

SPECIFICATION forming part of Letters Patent No. 547,210, dated October1, 1895.

Application filed September 27, i893. seriaifo. 486,639. (Model.)

Improvements in Marine Propellers, of which the following is a full,clear, and exact de scription, reference being had to the accom-`panying drawings, forming a part of this specification.

My invention relates to improvements in that class of marine propellersknown as screw propellers, in which heretofore thel propeller-bladeshave generally consisted of sections of a double, triple, or quadruplescrew or conveyer radiating from a common hub,

the many types thereof being now so common and well understood in theart as to require no further description beyond the bare statement thatthe nearest approach to my inven` tion known to me is that class ofscrew propellers in which the blades are spirally dis` posed upon acylindrical hub, and therefore radiate therefrom in varying planesintersecting the axis of the hub or the axis of rotation of thepropeller at right angles thereto. The objections to these prior formsof screw pro pellers, arising from the slip and drag which necessarilyaccompany such construction, are also well understood in the art ofmarine engineering, and allowance is generally made for a loss of atleast a third ofthe effective horse-power, which is offset by the slipand drag of the propeller; and yet a further and important objection tothis class of propellers is the danger of fracture of the blades, whichradiate unsupported from the center or hub of the propeller.

The prime object of this invention is to avoid the drag to which theprior form of propellers are subjected and at the same time to reducethe slip to the minimum, thereby securing the maximum efficiency inpropelling force.

Another object is to avoid the danger of breaking or fracturing thescrew-blades by having the propeller of such form that the blades affordmutual support to eachother at their outer ends..

These objects are attained by the devices illustrated in theaccompanying drawings, in which-e Figure l is a front elevation of apropeller embodying my invention; Fig. 2, a side elevation thereof gFig. 3, a rear elevation of the same, and Fig. 4 a side elevationthereof in the position shown in Fig. 1.

Similar letters of reference indicate the same parts in the severalfigures of the drawings.

Referring by letter to the accompanying drawings, A indicates the hub,perforated longitudinally for reception of the shaft, or in any knownand suitable manner arranged for the application of rotative powerthereto. From this hub or center revolve the blades G, G', H, and H',each blade being the duplicate of the other, and there being any desirednumber of such blades revolving from the same hub. r The plane of thesurface of each blade G, G', H, and H constantly changes from the tip orouter end thereof to the butt or point of its attachment to the hub, theplanes preferably not intersecting the axis of the hub, althoughthroughout the length 'thereof extending at a generally oblique angle tosaid axis, the angularity increasing from the tip or outer end to thebutt of the blade. These blades, it will be observed, are in the form ofinvolute spirals,

vevolving from the centers at opposite sides of the axis of the hub andat an angle thereto, and this distinctive feature of the blades, in theform of involute spirals at an angle 'to the axis of their support, Iregard as the essential and novel feature of my invention.

A propeller provided with my involute spiral blades has nearly doublethe working area of the ordinary radial concentric spiral blades, andtherefore a proportionate increase in etliciency for the same powerexpended, while the shape of the blades is such that practically alldrag is avoided and the slip thereof reduced to the minimum. `In thisconstruction the involute spiral blades are arranged at an angle to theaxis of the hub A, all evolving from the same hub, but cut away at theirbutts, as shown, so as to produce practically continuous surfaces. Itwill also be noted that the blades G and H are evolved from the samecenter, though at opposite angles to each other, while the blades G andH are also evolved from the same center, but at opposite angles to eachother and at the opposite side of the axis from IOO the center of theblades G and H. As a result of this disposition of the blades the tip orpoint of the blade G intersects the tip or point of the blade H, whilethe tip of the blade H intersects the point of the blade G', and atthese points of intersection the blades are united, either integrally orotherwise, so as to afford mutual support and thereby avoid tho dangerof fracture of the blades, to which those of the single-propeller typeare subjected.

A propeller of this compound type operates exactly the same whetherpropelling a vessel ahead or astern, for, assuming the vessel to bemoving in the direction indicated by the arrow I in Figs. 2 and 4 andthe propellers to be rotating in the direction of the arrows J in saidfigures, the inner surfaces K ofthe blades H and Il and the outersurfaces L of the blades G and G are the operating faces of the blades,while on reversing the propeller to send the vessel astern the outerfaces M of the blades H and H and the inner faces N of the blades G andG will become the operating surfaces, the effect in both cases being thesame. This will be better understood by assuming the curved arrows O inFigs. l and 3 to indicate the direction of rotation of the propellerwhen viewed from the front and rear, respectively,'corresponding withthe direction of rotation indicated by the arrows J in Figs. 2 and 4.Thus it will be seen that two of the blades are pulling and two pushingin either direction that the propeller may be revolving, and thepropeller will therefore have practically as great efficiency inpropelling the Vessel astern as in propelling it ahead, the maindifference in the eflicieucy being due to the advantage of the wakewhich follows the vessel in propelling ahead.

This compound propeller not only avoids practically all of theobjections to the prior forms of propeller, but also possesses theadvantages over the prior single form of propellers of the maximumstrength and rigidity, avoiding all danger of breakage or fracture ofthe blades, giving greatly increased working area and consequentlypropelling force, besides working with practically equal efficiency inpropelling a vessel either ahead or astern.

It will be observed that in the propeller hereinbefore described theblades are not only in the form of involute spirals, and therefore .arenot sections of a screw, but they are also straight in cross sectionthroughout their length, except, of course, at their edges, where themetal may be worked away to form a sharper edge, or where the blade maybe slightly thickened at its center for additional strength, the purposebeing to have the blade Substantially straight in cross sectionthroughout the length thereof, so that the angularity or inclination ofthe blades with relation to either their individual axes or the axis ofthe propeller will gradually decrease from' thek points to the butts ofthe blades. None of the lines delineating the plane of the differentparts of the propeller-blade radiate from the axis of the propeller,although they do radiate from their individual axes, but at constantlychanging oblique angles thereto, all of such lines radiating from asingle point., as would the lines delineating the surface of a coneradiate from the apex thereof.

Having described my invention, what I claim as new therein, and desireto secure by Letters Patent, is

l. A propeller, the blades of which are in the form of involute spiralsarranged at angles to the axis of the propeller shaft and one half ofsaid blades at angles reverse to the other, all of said blades beingstraight in crosssection, substantially as described.

2. A propeller, the blades of which are in the form of involute spirals,arranged at angles to the axis of the propeller shaft, and one-half ofsuch blades being arranged at the reverse angle to the other half withtheir outer ends intersecting and united, all of said blades beingstraight in cross-sectiou, substantially as described. v

3. A propeller, the blades of which are in the form of involute spiralswhose axes are parallel with, but eccentric to, the axis of thepropeller shaft, one half of such blades being arranged at the reverseangle to the other half, with their outerends intersecting and united,and all of said blades being straight in cross-section and decreasing ininclination or an gularity, with relation to their respective axes, fromtheir points of intersection to their butts substantially as described.

HERMANN HAUSSMANN.

Witnesses:

W. R. OMoHUNDRo, JNO. L. CONDRON.

ICO

